New for Driver Development Tools
In previous versions of Windows, these two functions did not filter their output -- all output passed to these functions was automatically sent to the kernel debugger. The functions DbgPrintEx and KdPrintEx were used for filtered output.
In Windows Vista, DbgPrint and KdPrint filter their output as well. If your driver uses these functions, you may no longer see your messages in the kernel debugger.
It is recommended that all drivers use DbgPrintEx and KdPrintEx, because these allow you to customize the filtering of your messages.
For more information, see Reading and Filtering Debugging Messages.